Dynamic Web TWAIN: How to download images directly from Database?

"Once a scan is added into the database, can it later be brought out of the DB and back into the Web TWAIN for viewing?"

You can use the method HTTPDownloadEx to achieve this.

1. On the server, add an action page to fetch the image data from the database and send it back to the client browser.

Here we take C# and MSSQL as an example:

<%@ Page Language="C#"%>
   ??/Get the image data from the database
   try//Send the image data to the client as stream    |
        String fileNameEncode;
        fileNameEncode = HttpUtility.UrlEncode(strImageName, System.Text.Encoding.UTF8);
        fileNameEncode = fileNameEncode.Replace("+", "%20");
        String appendedheader = "attachment;filename=" + fileNameEncode;
        Response.AppendHeader("Content-Disposition", appendedheader);
        Response.OutputStream.Write(byFileData, 0, byFileData.Length);
    catch (Exception)
catch (Exception)
{ }

2. On the client side, use the method HTTPDownloadEx to download the image. Put the action page DownloadFromDB.aspx as the source of the image (as the 2nd parameter "String HTTPRemoteFile"):

//downloadsource should be the correct path for 
//the page DownloadFromDB.aspx plus any necessary
//parameters needed for fetching the image(s)
var downloadsource = DownloadFromDB.aspx + 
//You should know the type of the image you are
//downloading because it?? downloading as a stream
//and Dynamic Web TWAIN needs the correct type
//in order to process the stream correctly
DWObject.HTTPDownloadEx(strHTTPServer, downloadsource,<%=strImageFileType %>);